Hey,
Thanks for your sharing .
When did you write summary during your studying or after you reading the book so mang times?
I ask this because your writing so logical.When I finish one chapter, I still cannot give just a globe logical for the whole book.
I mean this:
Here is the general plan:

Part I: File spacing.
Part II: Line Numbering.
Part III: Calculations.
Part IV: String creation. Array creation.
Part V: Text conversion and substitution.
Part VI: Selective printing and deleting of certain lines.
Part VII: Release of perl1line.txt.

How do you make your plan when first started.I'm lack of this skill, can you give me a suggest in improving this skill. Thanks so much!